This application is based on Application No. 2001-134061, filed in Japan on May 1, 2001, the contents of which are hereby incorporated by reference.
1. Field of the Invention
The present invention relates to operation management of a plurality of elevators installed inside a building, and a communications control system for elevators capable of decreasing both waiting time that an elevator passenger waits to board an elevator and waiting time that the elevator passenger waits to arrive at a desired target floor, and also is resistant to failure.
2. Description of the Related Art
Explanation is made of a conventional communications control system for elevators, making reference to the drawings.
FIG. 21 is a diagram showing a construction of a conventional communications control system for elevators shown in Japanese Patent Application Laid-open No. Hei 6-80322.
In this conventional communications control system for elevators, as shown in FIG. 21, three control units 91, 92 and 93 for controlling three elevators are provided as an example.
Each control unit 91, 92 and 93 has a car control unit CCa, CCb and CCc each controlling its own elevator, and in addition to this, each control unit 91, 92 and 93 is integrally equipped with a group control unit GCa, GCb and GCc for group management control processing being made compact for distributed processing, and a hall control unit HCa, HCb and HCc for hall call control processing.
Each control unit 91, 92 and 93 additionally has an LSI (large-scale integrated circuit) Sa, Sb and Sc for transmitting, and information output from these is transmitted via a bus-form high speed transmission line 94.
On the hall side, corresponding to the way this example is configured into two series, a hall controller 95 comprising a one-chip microcomputer (one-chip micon) is provided for each series of each hall. Each hall controller 95 is expressed by both a number (1 or 2) following the symbol S for indicating the series type and a number (1-m) for indicating the hall type. For example, the hall controller 95 on series 1 side at floor m is specified as S1m.
These hall controllers 95 perform, for example, input processing of a hall call registration signal from a hall call registration button 96 and output processing of a lighting signal to a hall call registration lamp 97. Further, these hall controllers 95 are connected in a parallel fashion to a master node CPU Ma, Mb and Mc of each control unit 91, 92 and 93 via a transmission line 98, 99 in each series.
Any one of the plurality of control units 91-93 is set as a main unit for dividing up work among the elevators and establishing synchronization among each control unit. The other control units are configured as sub units obeying the above-mentioned main unit. Control functions requiring real time processing are processed by the main unit performing control processing on the control units of all the series in a synchronized fashion. Control functions requiring cyclic processing are processed by dividing them up among the control units of each series.
The conventional communications control system for elevators described above had a problem in that synchronization instructions for the cyclic processing caused a useless burden for the sub units that was not clearly related to the given communication.
Further, in the case of the conventional communications control system for elevators described above, there was a problem that when a method was used such that the sub unit side detected collisions of transmissions and staggered transmission times, when there were ten-plus sub units or more, answer collisions were expected, and in order to receive all answers, the waiting times of the main unit became widely varied. Transmission of large amounts of faulty data generated with the answer collisions caused the network to be weighed down with useless traffic.
Further, in the case of the conventional communications control system for elevators mentioned above, it is considered that network break up and failure cause data collisions on the network. Thus, there was a problem in that it was difficult to transmit and receive data correctly at all units, and furthermore, there was a possibility that network break up may cause all the main units to disappear. When time was taken up for restoring failures caused by such erroneous processing, there was a possibility that serious trouble may be caused in the operation of the elevator which handles human life.
Further, in the case of the conventional communications control system for elevators mentioned above, it is considered that when network connection failure causes two or more networks to collide, the simultaneous operation of two or more main units may create a data collision on the network. Thus, there was a problem that it was difficult to simultaneously transmit synchronization instructions separately and transmit and receive data correctly at all units. Furthermore, there was a possibility that the collision may cause all the main units to disappear. When time is taken up for restoring failures caused by such erroneous processing, there was a possibility that serious trouble may be caused in the operation of the elevator which handles human life.
Next, explanation is made of a master conflict control method according to a conventional communications control device, making reference to the drawings.
FIG. 22 shows a construction of a communications control system shown in Japanese Patent Application Laid-open No. Hei 9-149061. The communications control device shown in FIG. 22 provides a conflict method for performing a unique control in the case when a plurality of masters mistakenly exist on the same transmission channel. In order to enable transition to a master in response to instructions from a superior calculator, each control station 82 has a master function 83.
Control stations 82 having become masters issue master notifications at predetermined periods containing their respective priority levels, and simultaneously transmit them. However, in the case when a control station 82 that has received a master notification is also in master status itself, the priority level of the master notification and the priority level of this control station 82 are compared, and in the case when this control station 82 has a lower priority it becomes a slave.
However, in the case of the conventional communications control device mentioned above, a node behaving as a master sends synchronization start data to one slave among a plurality of slaves, receives synchronization completion data from the slave, and then sends subsequent synchronization start data to a subsequent slave in order. However, there was a problem that when synchronization start data and synchronization completion data are transmitted and received to and from the slaves in this way, the synchronization start data and the synchronization completion data occupy a large proportion of the data relative to the elevator operation that is originally supposed to be transmitted and received. Thus, the network load on both the masters and the slaves increased.
The present invention was developed to solve the above-mentioned problems. Therefore, an object of the present invention is to obtain a communications control device for elevators in which synchronization instructions do not create a load on data reception in all the units and which is capable of realizing smooth data transfer.
In order to attain the above object, according to an aspect of the present invention, a communications control system for elevators having a plurality of control units including respective car control units and elevator hall registration control units, each of said plurality of control units having a node, the plurality of nodes being connected to each other via a network, and each of said node having a management table establishing correspondence between a node number and a network address, said elevator communications control system comprising: a node acting as a master when, in the case where a first network address corresponding to the node number of this node is, upon referring to the management table, a specific address in the management table, this node sends to all other nodes a broadcast communication to notify that this node is a temporary master having the first network address added thereto and receives from another temporary master a broadcast communication for notifying that this other node is the temporary master having a second network address corresponding to the node number of this other temporary master added thereto, if the first network address and the second network address conform to specific conditions; and a node acting as a slave when, in a case where the network address corresponding to the node number of this node is not a specific address in the management table or the first network address corresponding to the node number of this node is a specific address in the management table upon referring to the management table, this node sends to all other nodes a broadcast communication to notify that this node is a temporary master having the first network address added thereto and receives from another temporary master a broadcast communication for notifying that this other node is the temporary master having a second network address corresponding to the node number of this other temporary master added thereto, if the first network address and the second network address do not conform to specific conditions, wherein said node acting as the master sends synchronization start data to one slave from among a plurality of slaves; receives synchronization completion data from the slave to send subsequent synchronization start data to a subsequent slave in order; and adjusts the timing for sending synchronization start data so that it matches a target cycle, assuming that an interval for sending the synchronization start data is a synchronization start data sending cycle, based on; an amount of time from the sending of the synchronization start data until the receiving of the synchronization completion data; an amount of time required for sending the data, being calculable from a number of sending data stored in a sending buffer until the time of sending; and a target time for the synchronization start data sending cycle.
According to another aspect to of the present invention, each of said nodes on the network monitors a network connection, stops at a time when the connection is electrically (physically) severed while maintaining the state immediately before the connection is severed, and continues monitoring the network connection, and wherein both the master node and slave nodes join the network in the state immediately before the connection is severed at a time when the network is restored and reconnection occurs.
According to another aspect to of the present invention, at the time when the network is restored, a node having a specific address as the master in the management table joins as the master at the time of the reconnection, even in the case when the node was a slave immediately before the connection was severed.
According to another aspect to of the present invention, in the case when the network is physically (electrically) severed and restoration takes place in each of the two severed networks takes and nodes operating as the masters on each of the networks are controlling those networks, when the severed connection is reconnected and a single network is formed again, the master nodes of each network compete for a master right of the single network, a single node capable of acquiring the master right is determined based on a compound condition of:
(1) a condition determined by judgment as to whether there exist slave nodes on the networks of the competing nodes or not; and
(2) a condition determined by comparison of priority levels being defined by the network addresses in the management tables.
According to still another aspect to of the present invention, moving of the master right in the above-mentioned network to another node (slave) is realized by negotiation between the host CPUs of the nodes via the network.